秘钥加密解密（解密必须秘钥）

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

public class DESEncryptUtil {

	/**
	 * @description: DES加密/解密工具类
	 * @param args
	 * @throws Exception 
	 * @createDate 2013-3-20;下午01:18:19
	 */
	public static void main(String[] args) throws Exception {
		String input = "张飞";
		String key = "123456";
		
		DESEncryptUtil des = new DESEncryptUtil();
		
		String result = des.encryption(input, key);
		System.out.println("加密串："+result);
		
		System.out.println("解密串："+des.decryption(result, key));

	}


	private static final String DES_ALGORITHM = "DES";
			
		/**
		 * DES加密
		 * @param plainData 需加密的串
		 * @param secretKey 密钥
		 * @return
		 * @throws Exception
		 */
		public String encryption(String plainData, String secretKey) throws Exception{

			Cipher cipher = null;
			try {
				cipher = Cipher.getInstance(DES_ALGORITHM);
				cipher.init(Cipher.ENCRYPT_MODE, generateKey(secretKey));
				
			} catch (NoSuchAlgorithmException e) {
				e.printStackTrace();
			} catch (NoSuchPaddingException e) {
				e.printStackTrace();
			}catch(InvalidKeyException e){
				
			}
			
			try {
				// 为了防止解密时报javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher异常，
				// 不能把加密后的字节数组直接转换成字符串
				byte[] buf = cipher.doFinal(plainData.getBytes());
				
				return Base64Utils.encode(buf);
				
			} catch (IllegalBlockSizeException e) {
				e.printStackTrace();
				throw new Exception("IllegalBlockSizeException", e);
			} catch (BadPaddingException e) {
				e.printStackTrace();
				throw new Exception("BadPaddingException", e);
			}
		    
		}

		/**
		 * DES解密
		 * @param secretData 需解密的串
		 * @param secretKey 密钥
		 * @return
		 * @throws Exception
		 */
		public String decryption(String secretData, String secretKey) throws Exception{
			
			Cipher cipher = null;
			try {
				cipher = Cipher.getInstance(DES_ALGORITHM);
				cipher.init(Cipher.DECRYPT_MODE, generateKey(secretKey));
				
			} catch (NoSuchAlgorithmException e) {
				e.printStackTrace();
				throw new Exception("NoSuchAlgorithmException", e);
			} catch (NoSuchPaddingException e) {
				e.printStackTrace();
				throw new Exception("NoSuchPaddingException", e);
			}catch(InvalidKeyException e){
				e.printStackTrace();
				throw new Exception("InvalidKeyException", e);
				
			}
			
			try {
				
				byte[] buf = cipher.doFinal(Base64Utils.decode(secretData.toCharArray()));
				
				return new String(buf);
				
			} catch (IllegalBlockSizeException e) {
				e.printStackTrace();
				throw new Exception("IllegalBlockSizeException", e);
			} catch (BadPaddingException e) {
				e.printStackTrace();
				throw new Exception("BadPaddingException", e);
			}
		}
		
		
		/**
		 * 获得秘密密钥
		 * 
		 * @param secretKey
		 * @return
		 * @throws NoSuchAlgorithmException 
		 */
		private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException{
//			SecureRandom secureRandom = new SecureRandom(secretKey.getBytes());
			
			//防止linux下 随机生成key
			 SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
			 secureRandom.setSeed(secretKey.getBytes());
					
			// 为我们选择的DES算法生成一个KeyGenerator对象
			KeyGenerator kg = null;
			try {
				kg = KeyGenerator.getInstance(DES_ALGORITHM);
			} catch (NoSuchAlgorithmException e) {
			}
			kg.init(secureRandom);
			//kg.init(56, secureRandom);
			
			// 生成密钥
			return kg.generateKey();
		}
			
	/*	private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException,InvalidKeyException,InvalidKeySpecException{
			
			 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES_ALGORITHM);
			
			 DESKeySpec keySpec = new DESKeySpec(secretKey.getBytes());
			
			 keyFactory.generateSecret(keySpec);
			
			  return keyFactory.generateSecret(keySpec);
			
		}*/

		
		static class Base64Utils {

			static private char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();
			static private byte[] codes = new byte[256];
			static {
				for (int i = 0; i < 256; i++)
					codes[i] = -1;
				for (int i = 'A'; i <= 'Z'; i++)
					codes[i] = (byte) (i - 'A');
				for (int i = 'a'; i <= 'z'; i++)
					codes[i] = (byte) (26 + i - 'a');
				for (int i = '0'; i <= '9'; i++)
					codes[i] = (byte) (52 + i - '0');
				codes['+'] = 62;
				codes['/'] = 63;
			}
			
			/**
			 * 将原始数据编码为base64编码
			 */
			static public String encode(byte[] data) {
				char[] out = new char[((data.length + 2) / 3) * 4];
				for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {
					boolean quad = false;
					boolean trip = false;
					int val = (0xFF & (int) data[i]);
					val <<= 8;
					if ((i + 1) < data.length) {
						val |= (0xFF & (int) data[i + 1]);
						trip = true;
					}
					val <<= 8;
					if ((i + 2) < data.length) {
						val |= (0xFF & (int) data[i + 2]);
						quad = true;
					}
					out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];
					val >>= 6;
					out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];
					val >>= 6;
					out[index + 1] = alphabet[val & 0x3F];
					val >>= 6;
					out[index + 0] = alphabet[val & 0x3F];
				}
				
				return new String(out);
			}

			/**
			 * 将base64编码的数据解码成原始数据
			 */
			static public byte[] decode(char[] data) {
				int len = ((data.length + 3) / 4) * 3;
				if (data.length > 0 && data[data.length - 1] == '=')
					--len;
				if (data.length > 1 && data[data.length - 2] == '=')
					--len;
				byte[] out = new byte[len];
				int shift = 0;
				int accum = 0;
				int index = 0;
				for (int ix = 0; ix < data.length; ix++) {
					int value = codes[data[ix] & 0xFF];
					if (value >= 0) {
						accum <<= 6;
						shift += 6;
						accum |= value;
						if (shift >= 8) {
							shift -= 8;
							out[index++] = (byte) ((accum >> shift) & 0xff);
						}
					}
				}
				if (index != out.length)
					throw new Error("miscalculated data length!");
				return out;
			}
		}
}